Microsoft has revamped the existing labs in the training kit and added a few new ones.

The lab dubbed "Using Windows Phone Launcher and Choosers In Your Applications" exposes the APIs that developers can tap into when writing their apps to run common tasks, such as making phone calls, sending e-mail, and snapping photos.

The lab called "Understanding the Windows Phone Application Lifecycle (handling Tombstone)" delves into "tombstoning," or what happens when when a person navigates away from an app and the OS thus ends the app's process--a necessary task since Windows Phone 7 does not support application multitasking.

The new labs include "Hello Phone," a variation of the familiar "Hello World" program that developers create when learning a new programming language. This lab helps developers learn to use Microsoft Visual Studio 2010 Express for Windows Phones and Expression Blend to build their apps, according to Microsoft.

The lab on "Building Your First Windows Phone Application" presents a puzzle game designed to take developers on a tour of the different stages of creating an app. The "Windows Phone Navigation and Controls" explains how to navigate among the different screens in a Windows Phone Silverlight app. And the "Game Development with XNA Framework for Windows Phone" teaches developers how to create a basic XNA game app for the phone.